1. Field of the Invention
The present invention relates to a processing method in which a processing is carried out that deforms a part of an image fiber in the radial direction, wherein the deformation of the cores forming the image fiber and functioning as pixels becomes substantially identical for all the cores, and the improvement in the image quality at the center region and the peripheral region of the image fiber in the radial direction becomes substantially identical.
2. Description of the Related Art
Conventionally, the center region of an image fiber used in a fiber scope, for example, is heated and softened, and by carrying out a twisting process in which the image fiber is twisted or a bending process in which the image fiber is bent, improvement in the image quality of the transmitted image and inversion or the like of image direction can be carried out.
In particular, where the object is improvement of the quality of the transmitted image, there is a method of applying a twist having a small pitch to a part of the image fiber. Thereby, the core that functions as a pixel is deformed, the clad mode of the transmitted light from the deformed part of this core is dispersed to the outside, the light that becomes noise is eliminated, and thereby, the contrast in the image can be increased.
However, when applying such a twist with a small pitch, as is schematically shown in FIG. 7, the amount of deformation of the core at the center part 1a of the image fiber 1 in the radial direction becomes smaller than the amount of deformation of the core at the peripheral region 1b. Thus, when trying to sufficiently improve the image quality at the center region 1a, if the amount of the twist becomes large, the amount of deformation of the core at the peripheral region 1b becomes excessive, and there is a concern that the image may be broken up, and the quality of the image at the peripheral region 1b, to the contrary, deteriorates.
For example, Japanese Patent No. 2925173, Japanese Unexamined Patent Application, First Publication, No. 2000-185931, Japanese Examined Patent Application, Second Publication, No. Hei 6-42008, and Japanese Unexamined Patent Application, First Publication, No. Hei 10-123411 disclose a related art to carrying out such a deformation process on image fibers.
Thus, the problem to be solved by the present invention is applying a deforming process to a part of the image fiber, and when implementing an improvement of the quality of the transmitted image, the improvement of the image quality at the center region and the peripheral region of the image fiber in the radial direction is substantially identical, and thereby a uniform improvement of the entire screen is attained.